The AN/UQQ-2 Surveillance Towed Array Sensor System (SURTASS), colloquially referred to as the ship's "Tail", is a towed array sonar system of the United States Navy.
SURTASS Twin-Line consists of either the long passive SURTASS array or the Twin-line array, consisting of two shorter passive arrays towed side by side. The Twin-line Engineering Development Model was installed on USNS Assertive, and the first production model was installed on USNS Bold.[1] Neither ship still serve as SURTASS units.
As of 2009[update], SURTASS was deployed on the four Victorious-class vessels and the USNS Impeccable (T-AGOS-23) (a small-waterplane-area twin hull (SWATH) vessel).[2]